Who are the relevant actors in the creation of Chile's national foreign policy and what structures do they operate within?
Chile's current Constitution was approved in a national plebiscite in 1980 during the military dictatorship. It has since been amended nine times, but retains the strong executive tradition common in Chile since the end of the Parliamentary Republic in 1925.
The government is divided between an executive branch, containing 20 ministries; a bicameral legislature, consisting of a 47 member Senate and a 120 member Chamber of Deputies; and a Judiciary branch. Foreign policy is controlled by the executive branch through the Ministry of Foreign Relations. This ministry is in charge of "planning, directing, coordinating, executing, and diffusing the foreign policy formulated by the President of the Republic." 
It is responsible for coordinating all activities of all the other state ministries and public institutions as well as overseeing all issues related to national sovereignty including its marine and Antarctic territories. There is also a National Security Council, made up of the Presidents of the Senate, the Supreme Court and the Chiefs of each branch of the armed forces that advises the president of the Republic on defense issues. This division of powers gives the executive ample room to maneuver in international affairs. 
The current president of Chile is Michelle Bachelet (b.1951), a socialist, pediatrician and former health (2000 – 2002) and defense minister (2002 – 2004). Chile's current Foreign Minister is Alejandro Foxley, a member of the Christian Democratic Party, an economist and a politician who previously served as a senator (1998 – 2006) and finance minister (1990 – 1994).
Vanden, Harry E. y Gary Prevost. Politics of Latin America: The Power Game. Oxford University Press: Oxford 2002: 446  Chilean Ministry of Foreign Relations. Website 17 Apr. 2008